mirror of
https://gitlab.gnome.org/GNOME/gtk.git
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430 lines
13 KiB
C
430 lines
13 KiB
C
/* Images
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* #Keywords: GdkPaintable, GtkWidgetPaintable
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*
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* GtkImage and GtkPicture are used to display an image; the image can be
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* in a number of formats.
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*
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* GtkImage is the widget used to display icons or images that should be
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* sized and styled like an icon, while GtkPicture is used for images
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* that should be displayed as-is.
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*
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* This demo code shows some of the more obscure cases, in the simple
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* case a call to gtk_picture_new_for_file() or
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* gtk_image_new_from_icon_name() is all you need.
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*/
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#include <gtk/gtk.h>
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#include <glib/gstdio.h>
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#include <stdio.h>
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#include <errno.h>
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#include "pixbufpaintable.h"
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static GtkWidget *window = NULL;
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static GdkPixbufLoader *pixbuf_loader = NULL;
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static guint load_timeout = 0;
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static GInputStream * image_stream = NULL;
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static void
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progressive_prepared_callback (GdkPixbufLoader *loader,
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gpointer data)
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{
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GdkPixbuf *pixbuf;
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GtkWidget *picture;
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GdkTexture *texture;
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picture = GTK_WIDGET (data);
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pixbuf = gdk_pixbuf_loader_get_pixbuf (loader);
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/* Avoid displaying random memory contents, since the pixbuf
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* isn't filled in yet.
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*/
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gdk_pixbuf_fill (pixbuf, 0xaaaaaaff);
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texture = gdk_texture_new_for_pixbuf (pixbuf);
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gtk_picture_set_paintable (GTK_PICTURE (picture), GDK_PAINTABLE (texture));
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g_object_unref (texture);
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}
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static void
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progressive_updated_callback (GdkPixbufLoader *loader,
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int x,
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int y,
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int width,
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int height,
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gpointer data)
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{
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GtkWidget *picture = GTK_WIDGET (data);
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GdkTexture *texture;
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texture = gdk_texture_new_for_pixbuf (gdk_pixbuf_loader_get_pixbuf (loader));
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gtk_picture_set_paintable (GTK_PICTURE (picture), GDK_PAINTABLE (texture));
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g_object_unref (texture);
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}
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static int
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progressive_timeout (gpointer data)
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{
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GtkWidget *picture = GTK_WIDGET (data);
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/* This shows off fully-paranoid error handling, so looks scary.
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* You could factor out the error handling code into a nice separate
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* function to make things nicer.
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*/
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if (image_stream)
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{
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gssize bytes_read;
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guchar buf[256];
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GError *error = NULL;
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bytes_read = g_input_stream_read (image_stream, buf, 256, NULL, &error);
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if (bytes_read < 0)
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{
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GtkAlertDialog *dialog;
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dialog = gtk_alert_dialog_new ("Failure reading image file 'alphatest.png': %s",
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error->message);
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gtk_alert_dialog_show (dialog, NULL);
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g_object_unref (dialog);
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g_error_free (error);
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g_object_unref (image_stream);
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image_stream = NULL;
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load_timeout = 0;
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return FALSE; /* uninstall the timeout */
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}
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if (!gdk_pixbuf_loader_write (pixbuf_loader,
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buf, bytes_read,
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&error))
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{
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GtkAlertDialog *dialog;
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dialog = gtk_alert_dialog_new ("Failed to load image: %s",
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error->message);
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gtk_alert_dialog_show (dialog, NULL);
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g_object_unref (dialog);
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g_error_free (error);
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g_object_unref (image_stream);
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image_stream = NULL;
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load_timeout = 0;
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return FALSE; /* uninstall the timeout */
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}
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if (bytes_read == 0)
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{
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/* Errors can happen on close, e.g. if the image
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* file was truncated we'll know on close that
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* it was incomplete.
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*/
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error = NULL;
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if (!g_input_stream_close (image_stream, NULL, &error))
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{
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GtkAlertDialog *dialog;
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dialog = gtk_alert_dialog_new ("Failed to load image: %s",
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error->message);
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gtk_alert_dialog_show (dialog, NULL);
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g_object_unref (dialog);
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g_error_free (error);
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g_object_unref (image_stream);
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image_stream = NULL;
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g_object_unref (pixbuf_loader);
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pixbuf_loader = NULL;
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load_timeout = 0;
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return FALSE; /* uninstall the timeout */
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}
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g_object_unref (image_stream);
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image_stream = NULL;
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/* Errors can happen on close, e.g. if the image
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* file was truncated we'll know on close that
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* it was incomplete.
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*/
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error = NULL;
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if (!gdk_pixbuf_loader_close (pixbuf_loader, &error))
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{
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GtkAlertDialog *dialog;
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dialog = gtk_alert_dialog_new ("Failed to load image: %s",
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error->message);
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gtk_alert_dialog_show (dialog, NULL);
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g_object_unref (dialog);
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g_error_free (error);
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g_object_unref (pixbuf_loader);
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pixbuf_loader = NULL;
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load_timeout = 0;
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return FALSE; /* uninstall the timeout */
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}
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g_object_unref (pixbuf_loader);
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pixbuf_loader = NULL;
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}
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}
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else
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{
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GError *error = NULL;
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image_stream = g_resources_open_stream ("/images/alphatest.png", 0, &error);
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if (image_stream == NULL)
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{
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GtkAlertDialog *dialog;
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dialog = gtk_alert_dialog_new ("%s",
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error->message);
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gtk_alert_dialog_show (dialog, NULL);
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g_object_unref (dialog);
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g_error_free (error);
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load_timeout = 0;
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return FALSE; /* uninstall the timeout */
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}
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if (pixbuf_loader)
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{
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gdk_pixbuf_loader_close (pixbuf_loader, NULL);
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g_object_unref (pixbuf_loader);
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}
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pixbuf_loader = gdk_pixbuf_loader_new ();
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g_signal_connect_object (pixbuf_loader, "area-prepared",
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G_CALLBACK (progressive_prepared_callback), picture, 0);
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g_signal_connect_object (pixbuf_loader, "area-updated",
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G_CALLBACK (progressive_updated_callback), picture, 0);
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}
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/* leave timeout installed */
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return TRUE;
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}
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static void
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start_progressive_loading (GtkWidget *picture)
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{
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/* This is obviously totally contrived (we slow down loading
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* on purpose to show how incremental loading works).
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* The real purpose of incremental loading is the case where
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* you are reading data from a slow source such as the network.
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* The timeout simply simulates a slow data source by inserting
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* pauses in the reading process.
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*/
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load_timeout = g_timeout_add (300, progressive_timeout, picture);
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g_source_set_name_by_id (load_timeout, "[gtk] progressive_timeout");
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}
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static void
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cleanup_callback (gpointer data,
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GObject *former_object)
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{
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*(gpointer**)data = NULL;
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if (load_timeout)
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{
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g_source_remove (load_timeout);
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load_timeout = 0;
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}
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if (pixbuf_loader)
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{
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gdk_pixbuf_loader_close (pixbuf_loader, NULL);
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g_object_unref (pixbuf_loader);
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pixbuf_loader = NULL;
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}
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if (image_stream)
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{
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g_object_unref (image_stream);
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image_stream = NULL;
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}
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}
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static void
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toggle_sensitivity_callback (GtkWidget *togglebutton,
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gpointer user_data)
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{
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GtkWidget *child;
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for (child = gtk_widget_get_first_child (GTK_WIDGET (user_data));
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child != NULL;
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child = gtk_widget_get_next_sibling (child))
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{
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/* don't disable our toggle */
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if (child != togglebutton)
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gtk_widget_set_sensitive (child, !gtk_toggle_button_get_active (GTK_TOGGLE_BUTTON (togglebutton)));
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}
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}
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GtkWidget *
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do_images (GtkWidget *do_widget)
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{
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GtkWidget *video;
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GtkWidget *frame;
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GtkWidget *vbox;
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GtkWidget *hbox;
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GtkWidget *base_vbox;
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GtkWidget *image;
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GtkWidget *picture;
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GtkWidget *label;
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GtkWidget *button;
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GdkPaintable *paintable;
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GIcon *gicon;
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if (!window)
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{
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window = gtk_window_new ();
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gtk_window_set_display (GTK_WINDOW (window),
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gtk_widget_get_display (do_widget));
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gtk_window_set_title (GTK_WINDOW (window), "Images");
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g_object_weak_ref (G_OBJECT (window), cleanup_callback, &window);
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base_vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 8);
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gtk_widget_set_margin_start (base_vbox, 16);
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gtk_widget_set_margin_end (base_vbox, 16);
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gtk_widget_set_margin_top (base_vbox, 16);
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gtk_widget_set_margin_bottom (base_vbox, 16);
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gtk_window_set_child (GTK_WINDOW (window), base_vbox);
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hbox = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 16);
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gtk_box_append (GTK_BOX (base_vbox), hbox);
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vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 8);
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gtk_box_append (GTK_BOX (hbox), vbox);
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label = gtk_label_new ("Image from a resource");
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gtk_widget_add_css_class (label, "heading");
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gtk_box_append (GTK_BOX (vbox), label);
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frame = gtk_frame_new (NULL);
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gtk_widget_set_halign (frame, GTK_ALIGN_CENTER);
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gtk_widget_set_valign (frame, GTK_ALIGN_CENTER);
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gtk_box_append (GTK_BOX (vbox), frame);
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image = gtk_image_new_from_resource ("/images/org.gtk.Demo4.svg");
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gtk_image_set_icon_size (GTK_IMAGE (image), GTK_ICON_SIZE_LARGE);
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gtk_frame_set_child (GTK_FRAME (frame), image);
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/* Animation */
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label = gtk_label_new ("Animation from a resource");
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gtk_widget_add_css_class (label, "heading");
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gtk_box_append (GTK_BOX (vbox), label);
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frame = gtk_frame_new (NULL);
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gtk_widget_set_halign (frame, GTK_ALIGN_CENTER);
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gtk_widget_set_valign (frame, GTK_ALIGN_CENTER);
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gtk_box_append (GTK_BOX (vbox), frame);
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paintable = pixbuf_paintable_new_from_resource ("/images/floppybuddy.gif");
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picture = gtk_picture_new_for_paintable (paintable);
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g_object_unref (paintable);
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gtk_frame_set_child (GTK_FRAME (frame), picture);
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/* Symbolic icon */
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label = gtk_label_new ("Symbolic themed icon");
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gtk_widget_add_css_class (label, "heading");
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gtk_box_append (GTK_BOX (vbox), label);
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frame = gtk_frame_new (NULL);
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gtk_widget_set_halign (frame, GTK_ALIGN_CENTER);
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gtk_widget_set_valign (frame, GTK_ALIGN_CENTER);
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gtk_box_append (GTK_BOX (vbox), frame);
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gicon = g_themed_icon_new_with_default_fallbacks ("battery-caution-charging-symbolic");
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image = gtk_image_new_from_gicon (gicon);
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gtk_image_set_icon_size (GTK_IMAGE (image), GTK_ICON_SIZE_LARGE);
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gtk_frame_set_child (GTK_FRAME (frame), image);
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/* Progressive */
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vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 8);
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gtk_box_append (GTK_BOX (hbox), vbox);
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label = gtk_label_new ("Progressive image loading");
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gtk_widget_add_css_class (label, "heading");
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gtk_box_append (GTK_BOX (vbox), label);
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frame = gtk_frame_new (NULL);
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gtk_widget_set_halign (frame, GTK_ALIGN_CENTER);
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gtk_widget_set_valign (frame, GTK_ALIGN_CENTER);
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gtk_box_append (GTK_BOX (vbox), frame);
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/* Create an empty image for now; the progressive loader
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* will create the pixbuf and fill it in.
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*/
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picture = gtk_picture_new ();
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gtk_picture_set_alternative_text (GTK_PICTURE (picture), "A slowly loading image");
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gtk_frame_set_child (GTK_FRAME (frame), picture);
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start_progressive_loading (picture);
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/* Video */
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vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 8);
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gtk_box_append (GTK_BOX (hbox), vbox);
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label = gtk_label_new ("Displaying video");
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gtk_widget_add_css_class (label, "heading");
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gtk_box_append (GTK_BOX (vbox), label);
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frame = gtk_frame_new (NULL);
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gtk_widget_set_halign (frame, GTK_ALIGN_CENTER);
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gtk_widget_set_valign (frame, GTK_ALIGN_CENTER);
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gtk_box_append (GTK_BOX (vbox), frame);
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video = gtk_video_new_for_resource ("/images/gtk-logo.webm");
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gtk_media_stream_set_loop (gtk_video_get_media_stream (GTK_VIDEO (video)), TRUE);
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gtk_frame_set_child (GTK_FRAME (frame), video);
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/* Widget paintables */
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vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 8);
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gtk_box_append (GTK_BOX (hbox), vbox);
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label = gtk_label_new ("GtkWidgetPaintable");
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gtk_widget_add_css_class (label, "heading");
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gtk_box_append (GTK_BOX (vbox), label);
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paintable = gtk_widget_paintable_new (do_widget);
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picture = gtk_picture_new_for_paintable (paintable);
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gtk_widget_set_size_request (picture, 100, 100);
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gtk_widget_set_valign (picture, GTK_ALIGN_START);
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gtk_box_append (GTK_BOX (vbox), picture);
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/* Sensitivity control */
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button = gtk_toggle_button_new_with_mnemonic ("_Insensitive");
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gtk_box_append (GTK_BOX (base_vbox), button);
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g_signal_connect (button, "toggled",
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G_CALLBACK (toggle_sensitivity_callback),
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base_vbox);
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}
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if (!gtk_widget_get_visible (window))
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gtk_widget_set_visible (window, TRUE);
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else
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gtk_window_destroy (GTK_WINDOW (window));
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return window;
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}
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